The possible role that lung may play as a metabolic organ remains an important problem to assess. This proposal outlines a research problem which will allow the Principal Investigator the time and support to develop an on-going investigatory program directly related to possible health-related studies of pulmonary diseases and pulmonary processes on a biochemical level. The initial aim will be to evaluate the similarities or differences in the mixed-function oxidase reactions which exist in the liver and lung of animals, such as, rat or hamster which are capable of eliciting lung tumorigenesis. These studies will also delineate the role of certain enzymes and proteins in xenobiotic metabolism of lung. The effect of acute and chronic exposure of drugs and carcinogens on these microsomal enzymes and their related activities will be studied to elucidate the regulatory controls which may exist in lung. Although this proposal primarily focuses on xenobiotic metabolism and possible cancer states of lung, the cause or treatment of other lung diseases could involve the mixed-function oxidases and would be included in the Principal Investigator's future research programs.